Ferrule having alignment features for polishing operations and an associated polishing jig and method

ABSTRACT

A ferrule is provided that includes a ferrule body defining a longitudinally extending groove that can serve as an alignment feature for polishing operations. In this regard, the ferrule body extends longitudinally between opposed front and rear surfaces so that at least the rear surface generally defines a substantially rectangular shape in lateral cross-section. In addition, the ferrule body typically has first and second major sides and first and second minor sides with the first and second major sides being larger than the first and second minor sides. The ferrule body defines the longitudinally extending groove in at least one of the major surfaces. A jig is also provided for engaging the longitudinally extending groove defined by the ferrule body in order to hold the ferrule in an aligned position during polishing operations. In this regard, the jig includes a jig body having an alignment feature for engaging a complimentary alignment feature of the ferrule. The jig also includes a support element capable of engaging another side of the ferrule, wherein at least one of the jig body and the support element is capable of pivoting. By appropriately sizing those elements of the jig body and the support element that contact the ferrule, the contact elements can be inserted through openings defined by the connector housing such that the front surface of the ferrule can be precisely polished after the ferrule has been assembled into a fiber optic connector.

FIELD OF THE INVENTION

[0001] The present invention relates generally to ferrules having apolished front surface and, more particularly, to ferrules havingalignment features to facilitate the polishing of their front surfacesfollowing the preassembly of the ferrules into connectors, as well as anassociated jig and method for holding a ferrule during polishingoperations.

BACKGROUND OF THE INVENTION

[0002] Optical fibers are utilized for a variety of applications,including data transmission and the like. In order to interconnect theoptical fibers, fiber optic connectors are mounted upon the end portionsof the optical fibers, and pairs of the fiber optic connectors arethereafter mated. In order to provide an optical connection with therelatively low attenuation and the small return loss demanded by manymodern applications, fiber optic connectors are generally designed suchthat fiber-to-fiber contact is established between the optical fibersupon which the respective fiber optic connectors are mounted. Forexample, fiber-to-fiber contact is preferably established between eachoptical fiber of a first fiber optic cable upon which a first-fiberoptic connector is mounted and the respective optical fibers of a secondfiber optic cable upon which a second fiber optic connector is mounted,once the first and second fiber optic connectors have been mated.

[0003] In order to establish fiber-to-fiber contact, the front surfaceof the ferrule of each fiber optic connector must be precisely formed toensure that the front surface is extremely smooth and planar and tominimize any angular errors relative to the optical fiber bores definedby the ferrule. In other words, the front surface of the ferrule ispreferably formed to define a planar surface that extends perpendicularto the longitudinal axes of the optical fiber bores. By way of example,the front face of most ferrules must generally have an angular error ofless than 0.2° relative to the optical fiber bores to ensure that theoptical fibers upon which the ferrule is mounted can be brought into dryphysical contact with the optical fibers of another fiber opticconnector.

[0004] Most ferrules are molded from a plastic material. Although theferrules are typically molded to within relatively specific tolerances,the front surfaces of the ferrule are generally unable to be molded tohave a sufficiently smooth front surface and to have a sufficientlysmall angular error. As such, the front surfaces of the ferrule mustgenerally be polished after the ferrule has been mounted upon the endportions of the optical fibers. Not only does the polishing serve tosmooth the front surface and to reduce the angular error of the frontsurface of the ferrule to within acceptable limits, such as less than0.2°, but the polishing also serves to ensure that the ends of theoptical fibers are properly positioned relative to the front surface ofthe ferrule, such as by either being flush with the front surface of theferrule or by protruding by a predetermined amount relative to the frontsurface of the ferrule.

[0005] The front face of the ferrule is generally polished to have apredetermined angular relationship, such as 90°, with respect to thelongitudinal axes of the optical fiber bores defined by the ferrule.Since the longitudinal axes of the optical fiber bores are inaccessiblefor use as a reference point or datum during polishing operations,ferrules are typically designed to have some other reference point ordatum that has a predefined positional or angular relationship withrespect to the longitudinal axes of the optical fiber bore. As such, thepolishing of the front face of the ferrule can be done with respect tothe datum that is accessible in order to appropriately polish the frontface of the ferrule relative to the longitudinal axes of the opticalfiber bores.

[0006] With respect to cylindrical single fiber ferrules, the outerdiameter of the cylindrical shaft portion of the single fiber ferrule istypically used as the datum. The cylindrical shaft portion of a singlefiber ferrule is an effective datum for polishing purposes for at leasttwo reasons. First, the outer diameter of the cylindrical shaft of asingle fiber ferrule has a predefined relationship with the longitudinalaxis of the optical fiber bore, namely, the longitudinal axes of theoptical fiber bore and the cylindrical shaft of the single fiber ferruleare usually coincident. Secondly, the outer diameter of the cylindricalshaft portion of a single fiber ferrule is required to be preciselyformed since the outer diameter of the cylindrical shaft of a singlefiber ferrule is also utilized to align the optical fiber upon which theferrule is mounted with another optical fiber during the process ofmating a pair of single fiber connectors. In this regard, the outerdiameter of the cylindrical shaft portion of a single fiber ferrule istypically formed to within a tolerance of one micron.

[0007] In order to polish the front face of the single fiber ferrule,the cylindrical shaft portion of the ferrule is positioned within aprecision bore defined by a polishing fixture. As will be apparent, theprecision bore has a precise size, such as to within a tolerance of onemicron or so, and a predetermined orientation. While the single fiberferrule is held by the precision bore of the polishing fixture, thefront surface of the single fiber ferrule is brought into contact withthe polishing media and polished.

[0008] While the outer diameter of a ferrule is an effective datum forcylindrical single fiber ferrules, the exterior dimensions of amultifiber ferrule are not generally defined to within such exactingtolerances since the exterior surfaces of a multifiber ferrule are notreferenced in the same fashion as the outer diameter of the cylindricalshaft portion of a single fiber ferrule during the interconnection of apair of multifiber connectors. In this regard, the outer surfaces ofmost multifiber ferrules are generally only formed to within tolerancesof five microns or more. As such, the exterior dimensions of amultifiber ferrule generally cannot serve as a polishing datum.

[0009] Since the exterior surface of a multifiber ferrule does notgenerally serve as a polishing datum, multifiber ferrules must includeother features to serve as a polishing datum. In this regard, theshoulder, or at least portions of the shoulder, defined between theshaft of a multifiber ferrule and the enlarged rear portion of amultifiber ferrule typically serves as a polishing datum. In thisregard, the shoulder of a multifiber ferrule is typically formed to bewithin fairly specific tolerances and to have a predefined relationshipwith respect to the longitudinal axes defined by the optical fiberbores, namely, a perpendicular relationship with respect to thelongitudinal axes defined by the optical fiber bores. However, theshoulder of a multifiber ferrule is typically inaccessible once themultifiber ferrule has been assembled within a connector housing of amultifiber connector. As such, the front face of a multifiber ferrulemust typically be polished after the multifiber ferrule has been mountedupon the end portions of a plurality of optical fibers, but prior toassembling the multifiber connector. Since the multifiber ferrule mustbe mounted upon the end portions of a plurality of optical fibers priorto assembling the multifiber connector, multifiber connectors are nottypically assembled in the factory, at which time the assembly processcould be efficiently performed in an automated fashion. Instead, amultifiber connector is typically assembled in the field once atechnician has mounted a multifiber ferrule upon the end portions of aplurality of optical fibers and the front surface of the ferrule hasbeen polished. As such, polishing the front surface of a multifiberferrule prior to assembling the multifiber connector decreases theefficiency with which the connector can be assembled and is generally amuch less cost effective technique for producing multifiber connectors.

[0010] While the exterior surfaces of a multifiber ferrule could beformed more precisely to serve as a polishing datum in much the samefashion as the outer diameter of a cylindrical single fiber ferrule, themanufacture of a multifiber ferrule having precisely formed exteriorsurfaces would disadvantageously increase the cost of the multifiberferrule. As such, multifiber ferrules are not generally formed withprecisely defined exterior surfaces for use as polishing datums eventhough the use of such precisely defined exterior surfaces as polishingdatums would permit a multifiber connector to be preassembled prior topolishing the front surface of the multifiber ferrule.

[0011] As described above, a variety of techniques are available forpolishing the front surface of the ferrule. With respect to multifiberferrules, however, conventional polishing techniques dictate that thefront surface be polished after the multifiber ferrule has been mountedupon the plurality of optical fibers, but prior to assembling themultifiber ferrule. In view of the increased costs and inefficienciesincurred to polish the multi fiber ferrule in a disassembled state andto then subsequently assemble a multifiber connector including thepolished ferrule in the field, it would be desirable to develop otherpolishing techniques to permit the front surface of a multifiber ferruleto be precisely polished following assembly of a multifiber connector.

SUMMARY OF THE INVENTION

[0012] A ferrule is therefore provided according to one embodiment ofthe present invention that includes a ferrule body defining alongitudinally extending groove that can serve as an alignment featurefor polishing operations. In this regard, the ferrule body extendslongitudinally between opposed front and rear surfaces so that at leastthe rear surface generally defines a substantially rectangular shape inlateral cross-section. In addition, the ferrule body typically has firstand second major sides and first and second minor sides with the firstand second major sides being larger than the first and second minorsides. According to the present invention, the ferrule body defines thelongitudinally extending groove in at least one of the major surfaces. Ajig is also provided according to another embodiment of the presentinvention for engaging the alignment feature of the ferrule body inorder to hold the ferrule in an aligned position during polishingoperations. In this regard, the jig includes a jig body that also has analignment feature for engaging the complimentary alignment feature ofthe ferrule and a support element having a support surface capable ofengaging another side of the ferrule, wherein at least one of the jigbody and the support element is capable of pivoting. As such, the frontsurface of the ferrule can be precisely polished after the ferrule hasbeen assembled into a fiber optic connector since the longitudinallyextending groove defined by the ferrule body that serves as thepolishing datum is accessible following assembly of the fiber opticconnector.

[0013] With respect to the ferrule of the present invention, thelongitudinally extending groove defined by the ferrule of oneadvantageous embodiment has a V-shape in lateral cross-section. In thisembodiment, the V-shaped groove is truncated such that the groove isdefined by a pair of sloping sidewalls and a bottom surface extendingbetween the pair of sloping sidewalls. Regardless of its shape, thegroove is preferably defined to extend longitudinally through a medialportion of the respective major surface. In this regard, the ferrulebody also typically defines a plurality of optical fiber bores and apair of guide pin openings on opposite sides of the optical fiber bores.As such, the groove is preferably disposed between the pair of guide pinopenings such that the strength and mechanical integrity of the ferruleis not significantly diminished, if at all. In addition, while theferrule body need only define a single longitudinally extending groovein one of the first and second major surfaces, the ferrule body of oneadvantageous embodiment defines a pair of longitudinally extendinggrooves with one groove defined by each of the first and second majorsurfaces. As such, the ferrule body of this advantageous embodiment issymmetric relative to a plane extending through the optical fiber boresand has a bowtie shape in lateral cross-section.

[0014] According to another aspect of the present invention, a polishingjig is also provided that includes an alignment feature for cooperatingwith the alignment feature of the ferrule to hold the ferrule in analigned position during polishing operations. In this regard, thealignment features of the ferrule and the polishing jig are selectedfrom a group consisting of a V-shaped alignment groove and an outwardlyprotruding alignment member having a semicircular shape incross-section. The alignment features of the ferrule and the polishingjig are therefore selected from the group such that the ferrule includesone type of alignment feature, such as the longitudinally extendinggroove as described above, and the polishing jig includes the other typeof alignment feature.

[0015] The polishing jig preferably includes a jig body having a contactelement that typically includes the alignment feature, and a supportelement having a support surface such that the ferrule is held in analigned position between the jig body and the support element.Typically, one of the support element and the jig body is capable ofpivoting about an axis perpendicular to the alignment feature of the jigbody to ensure that the ferrule is evenly supported or loaded across itsentire surface during the subsequent polishing operations. The supportsurface of the support element also preferably includes a contactelement, such as at least one rib, that protrudes outwardly relative tothe other portions of the support surface. By contacting the ferrulewith the contact element and not with the other portions of the supportsurface, the support element of this embodiment of the present inventionreduces the contact area and correspondingly reduces the deleteriousimpact of dirt that may have accumulated on the surface of the ferruleon the resulting alignment of the ferrule within the polishing jig. Inone advantageous embodiment, the contact element of the support elementincludes a pair of parallel ribs. Alternatively, the contact element ofthe support element can include a T-shaped rib.

[0016] The contact elements, such as the alignment feature of the jigbody and the ribs of the support element, are preferably sized such thatthe support elements can be inserted through corresponding openingsdefined by the connector housing. As such, the polishing jig of thepresent invention can engage a ferrule following preassembly of theconnector. As such, the front face of the ferrule can advantageously bepolished following assembly of the connector.

[0017] As described above, the alignment feature of the ferrule istypically a longitudinally extending groove. Correspondingly, thealignment feature of the jig is typically an outwardly protrudingalignment member, such an alignment rib carried by the jig body andadapted to engage the groove defined by the ferrule. In this regard, thegroove defined by the ferrule and the outwardly protruding alignmentmember carried by the jig body have cross-sectional shapes selected fromthe group consisting of a semicircular shape and a V-shape. Typically,the ferrule defines a V-shaped groove and the jig body includes anoutwardly protruding alignment member having a semicircular shape,although the ferrule can include the outwardly extending alignmentmember and the jig body can define the V-shaped groove, if so desired.

[0018] According to the present invention, the polishing jig cansecurely hold the ferrule in an aligned position during polishingoperations even after the ferrule has been assembled as part of thefiber optic connector. In this regard, by engaging the V-shaped groovedefined by the ferrule of one embodiment of the invention with anoutwardly protruding alignment rib having a semicircular cross-section,the jig body effectively establishes two lines of contact with theferrule. In addition, by supporting the opposite side of the ferrulewith the support element, a third region of contact is established,thereby insuring that the ferrule is held by the polishing jig in analigned and secure fashion even after the ferrule has been incorporatedinto a multifiber ferrule. As such, the longitudinally extending groovedefined by the ferrule can serve as the datum during polishing of thefront surface thereof, even after the ferrule has been assembled into aconnector.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view of a ferrule according to oneembodiment of the present invention.

[0020]FIGS. 2A and 2B are increasingly enlarged perspective views of ajig according to one embodiment of the present invention in which aferrule is held between a jig body and a pivotable support element.

[0021]FIG. 2C is a further enlarged perspective view of a jig holding aferrule, viewed from the opposite side of FIGS. 2A and 2B.

[0022]FIG. 3 is a perspective view illustrating the engagement of aferrule by portions of a jig including a jig body and an opposedpivotable support element according to one embodiment to the presentinvention in which the other portions of the jig and the multifiberconnector have been omitted for purposes of clarity.

[0023]FIG. 4 is a perspective view illustrating the engagement of aferrule by portions of a jig including a jig body and an opposedpivotable support element according to another embodiment to the presentinvention in which other portions of the jig and the multifiberconnector have also been omitted for purposes of clarity.

[0024]FIGS. 5A and 5B are fragmentary perspective views of a jigaccording to another embodiment of the present invention in which aferrule of a preassembled connector is held between a pivotable jig bodyand a support element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention now will be described more fullyhereinafter with reference to the accompanying drawings, in whichpreferred embodiments of the invention are shown. This invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout.

[0026] Referring now to FIG. 1, a ferrule 10 according to oneadvantageous embodiment of the present invention is depicted. Theferrule includes a ferrule body extending longitudinally between opposedfront and rear surfaces 12, 14. The ferrule of the present inventionalso includes an alignment feature that is accessible even after theassembly of a fiber optic connector that includes the ferrule such thatthe alignment feature can serve as a polishing datum during polishingoperations. Although the alignment feature can be an outwardlyprotruding alignment member, such as a longitudinally extendingalignment rib, the alignment feature is typically a longitudinallyextending groove 16 defined by the ferrule body. The outside surface ofthe ferrule itself may also act as the datum where precise tolerancescan be maintained-in a single fiber ferrule, for example.

[0027] As shown in FIG. 1, at least the rear surface 14 of the ferrule10 typically defines a substantially rectangular shape in lateralcross-section. As such, the ferrule body generally includes first andsecond major sides 11 and first and second minor sides 13. As will beapparent, the first and second major sides are larger or wider than thefirst and second minor sides 13. As shown in FIG. 1, the longitudinallyextending groove 16 is defined in at least one of the first and secondmajor surfaces 15 of the ferrule body. Although the ferrule need onlydefine a single longitudinally extending groove, the ferrule can definea pair of longitudinally extending grooves, one of which is defined ineach of the first and second major surfaces 15 as shown in FIG. 1. Inthis embodiment, the ferrule, which has a bowtie shape in lateralcross-section, will be symmetric relative to a plane that extendsthrough the optical fiber bores 18 defined by the ferrule. As a resultof its symmetry, the ferrule may be more easily assembled into a fiberoptic connector since its relative orientation is immaterial.

[0028] As shown in FIG. 1, the groove 16 defined by the ferrule 10preferably extends longitudinally through a medial portion of therespective major surface 15. In this regard, the ferrule is typically amultifiber ferrule so as to also define the plurality of optical fiberbores 18 and a pair of guide pin openings 19 on opposite sides of theoptical fiber bores. As such, the groove 16 defined by the ferrule ispreferably disposed between the pair of guide pin openings 19. Bydefining the groove 16 in a medial portion of the ferrule body, theferrule is not significantly weakened since a significant amount ofmaterial still exists between the groove 16 and the optical fiber bores19. However, the ferrule can define the groove at other locations, if sodesired.

[0029] The groove 16 defined by the ferrule 10 can have a variety ofshapes and lateral cross-sections, including a U or semicircular shape.However, the ferrule of one advantageous embodiment defines a groovethat has a V-shape in lateral cross-section. As shown in FIGS. 1 and 5B,the V-shaped groove can be a true V-shape or, as shown in FIG. 2C, theV-shaped groove can be truncated since the corresponding alignmentmember of the polishing jig generally only contacts the opposed sides ofthe groove and does not contact the bottom of the groove, as describedbelow. Also, as shown in FIG. 2C and 3, the V-shaped groove can beradiused. As such, the V-shaped groove is typically defined by a pair ofsloping sidewalls and a radiused or flat bottom surface extendingbetween the pair of sloping sidewalls. While the sidewalls can slope ata variety of angles without departing from the spirit and scope of thepresent invention, the sidewalls preferably slope at an angle of 30° to60° and, more preferably, at 45° relative to a plane extending throughthe optical fiber bores 18 defined by the ferrule.

[0030] While the position of the groove 16 relating to the front surface12 should be precisely defined, the groove can have a variety of sizessince the engagement of a V-shaped groove with an alignment memberhaving a semicircular shape in lateral cross-section is relativelyimmune to changes in the size and depth of the groove. In oneadvantageous embodiment in which the shaft portion of the ferrule 10 issized to be 4.4 mm by 2.45 mm, however, the grooves are centered withinthe respective major surfaces 15 and have a maximum width of 0.8 mm anda depth of 0.4 mm, and define sidewalls that slope at an angle of 45°.As shown in FIG. 1, the grooves 16 need not extend longitudinally alongthe entire length of the shaft of the ferrule. Instead, the grooves 16need only be defined by the forwardmost portion of the ferrule sinceonly the forwardmost portion of the ferrule will generally be exposedand can be accessed following assembly of the ferrule into a connector.In one embodiment in which the shaft portion of the ferrule has a lengthof 8 mm, the longitudinally extending grooves 16 have a length of 5 mm.However, the grooves 16 defined by the ferrule 10 can have other shapes,sizes, and lengths without departing from the spirit and scope of thepresent invention.

[0031] In order to polish the front surface 12 of the ferrule 10, theferrule is typically held by a polishing jig 20. While the polishing jigwill hereinafter be described in conjunction with the ferrule of FIG. 1,the polishing jig of the present invention can be adapted to hold bothrectangular and cyclindrical ferrules during polishing operationsconducted after preassembling the respective connectors.

[0032] With respect to the ferrule 10 of FIG. 1, however, the alignmentfeature of the ferrule, such as the lengthwise extending groove 16,preferably cooperates with a complimentary alignment feature or othercontact element of the polishing jig 20 such that the ferrule can beheld in an aligned position during polishing of the front surface 12thereof. According to the present invention, the alignment features ofthe ferrule and the polishing jig are selected from the group consistingof an alignment groove and an outwardly protruding alignment member. Inthis regard, the alignment features of the ferrule and the polishing jigare selected from the group such that the ferrule includes one type ofalignment feature and the polishing jig includes the other type ofalignment feature. As described above, the ferrule of the presentinvention preferably includes a lengthwise extending groove, such as aV-shaped alignment groove. As such, the polishing jig generally includesan outwardly protruding alignment member 22 that typically has asemicircular shape in cross-section. However, the ferrule can includethe outwardly extending alignment member and the polishing jig candefine the alignment groove, if so desired. (An extreme example would bea cylindrical ferrule and a corresponding element having a concaveshape.) For purposes of illustration, however, the polishing jig will behereinafter described as having an outwardly protruding alignment memberthat serves as the respective alignment feature.

[0033] The polishing jig 20 can be designed in many different fashionswithout departing from the spirit and scope of the present invention. Byway of example and not limitation, however, one embodiment of apolishing jig is shown in FIGS. 2A and 2B. In particular, the polishingjig of this embodiment includes a platform 23 that is typically fixed inposition. As illustrated, the platform can be a circular plate. However,the platform can have any desired shape. The polishing jig also includesa jig body 24. As shown in FIGS. 2A and 2B, the jig body 24 is mountedto the platform, such as the edge portion of the circular plate.However, the jig body 24 can be mounted to other components of the jigas described below, if so desired. The jig body 24 has or carries acontact element that serves as the alignment feature 22, such as theoutwardly protruding alignment member. The alignment member is capableof engaging the alignment feature, such as the groove 16, defined by theferrule 10 once the ferrule is placed in the polishing jig. In thisregard, the groove 16 defined by the ferrule 10 is preferably accessibleeven after the ferrule has been assembled into a connector. As known tothose skilled in the art and as illustrated and described in conjunctionwith FIGS. 5A and 5B, for example, a connector housing 40 can define ribslots or other openings 42 that are aligned with the groove defined bythe ferrule. Typically, the openings defined by the connector housingare proximate the forward end of the connector housing. However, theopenings can be defined by other portions of the connector housing, ifso desired, including holes or apertures in the connector housing. Inorder to permit the ferrule to be polished after the connector has beenassembled, the outwardly protruding alignment member of the jig body 24is preferably sized to be inserted through the rib slot or hole/aperturedefined by the connector housing and into engagement with the ferrule,and in the illustrated embodiment, the groove defined by the ferrule.While the polishing jig and the ferrule of the present invention aredesigned to permit the front surface 12 of the ferrule 10 to be polishedafter the ferrule has been assembled into a connector, it will be notedthat the polishing jig is depicted in FIGS. 2A-2C in conjunction with anindividual ferrule for the sake of clarity. However, another embodimentof a polishing jig will subsequently be depicted in conjunction with apreassembled connector by way of further illustration.

[0034] The alignment member 22 of the jig body 24 has a cross-sectionalshape that is designed to mate with the groove 16 defined by the ferrule10. Typically, the cross-sectional shape of the alignment member isselected from the group consisting of a semicircular shape and aV-shape. While a V-shaped alignment member can engage a V-shaped groovedefined by the ferrule, a semicircularly shaped alignment member canalso engage a V-shaped groove defined by the ferrule as best shown inFIGS. 2C, 3, and 4. In this regard, the engagement of a V-shaped groovedefined by the ferrule with an alignment member having a semicircularshape in lateral cross-section permits the alignment member to contactthe ferrule along two lines. For example, the alignment member of thejig body preferably contacts the ferrule along lines extendinglengthwise along both sloping sidewalls of the V-shaped groove. Inaddition, a semicircular alignment member does not engage the lowerportions of the V-shaped groove defined by the ferrule. As such, thesize and, in particular, the depth of the V-shaped groove need not beprecisely defined and can be rounded off as shown in FIG. 3.

[0035] While the alignment member 22 of the illustrated embodiment ofthe jig body 24 is a lengthwise extending alignment rib having asemicircular shape in lateral cross-section, the outwardly protrudingalignment member of the jig body can be formed in other manners, such asby means of a row of balls having precisely defined dimensions. Inaddition, the jig body can be formed such that the outwardly protrudingalignment member is a replaceable component. In this regard, while theoutwardly protruding alignment member is not anticipated to wear veryrapidly since the sliding contact between the alignment member and theferrule 10 will be minimized, some wear will occur over time and a jigbody having a replaceable alignment member will permit the alignmentmember to be easily replaced.

[0036] The polishing jig 20 also includes a support element 30 having asupport surface with a contact element capable of engaging another sideof the ferrule 10 opposite the side of the ferrule defining the groove16 that is engaged by the outwardly protruding alignment member 22 ofthe jig body 24. As such, the engagement of the ferrule by the supportelement establishes a third region of contact in order to securely holdthe ferrule. According to the present invention, at least one of thesupport element and the jig body is adapted to pivot or rotate relativeto the ferrule so as to uniformly support and evenly load the ferruleduring polishing operations. As shown in FIGS. 2C, 3 and 4, for example,the support element of one embodiment is capable of pivoting about anaxis 30′ perpendicular to the outwardly protruding alignment member.However, the jig body may, instead, be pivotable, if so desired.

[0037] The polishing jig 20 of the illustrated embodiment also includesa rotatable hub 26 and an arm 28 extending radially outward from thehub. As shown in FIGS. 2A-2C, the support element 30 is mounted upon adistal end of the arm and is positioned proximate the ferrule 10, albeiton an opposite side of the ferrule from the jig body 24. In addition,the arm can define a window 28 a through which the ferrule can protrudeduring polishing operations.

[0038] The arm 28 is typically mounted to the platform 23 and is capableof at least limited movement relative to the platform. For example, theplatform of the illustrated embodiment includes a pair of pins 23 aextending outwardly therefrom for engaging corresponding radial slots 28b defined by the arm. As such, the arm is capable of radial movementrelative to the platform as limited by the size of the radial slotsrelative to the pins. The polishing jig 20 can also include a biasmember, such as a spring, that urges the arm in a radially inwarddirection in the absence of other forces. Although not shown, the biasmember would typically have one end in contact with the arm and theother end in contact with the platform so as to urge the arm in a radialinward direction. While the polishing jig can be designed in manydifferent fashions, the arm of one embodiment includes a tab thatextends toward the platform, while the platform also includes a tab thatextends toward the arm and is radially spaced therefrom. As such, thebias member can be positioned between the arm and the platform, i.e.,proximate the side of the arm hidden from view in FIGS. 2A and 2B, suchthat the opposite ends of the bias members contact respective tabs andurge the arm radially inward in the absence of other forces.

[0039] The polishing jig 20 of the illustrated embodiment alsopreferably includes means for radially positioning the arm 28 relativeto the platform 23. While a variety of techniques can be employed toradially position the arm, the polishing jig of the illustratedembodiment includes the rotatable hub 26 that serves to radiallyposition the arm. In this regard, the hub includes a cam member 26 ahaving a protruding medial portion 26 b and recessed lateral portions 26c. As such, rotation of the hub relative to the platform such that theprotruding medial portion engages the proximal end of the arm andovercomes the radially inwardly directed bias force so as to cause thearm to be radially extended, thereby moving the support element 30 awayfrom and out of contact with the ferrule 10. Alternatively, rotation ofthe hub such that a recessed lateral portion engages the proximal end ofthe arm permits the bias member to draw the arm radially inward and intocontact with the ferrule.

[0040] Preferably, the support element 30 does not contact the ferrule10 across all portions of the support surface, since dirt or othercontaminants on the ferrule or support surface will reduce the precisionof the polishing of the front surface 12 of the ferrule if the dirt istrapped between the ferrule and those portions of the support surfacethat contact the ferrule. As such, the support element preferablyincludes a contact element, such as at least one rib 32, protrudingoutwardly relative to other portions of the support surface. The supportelement of this embodiment therefore contacts the ferrule with the rib,but not with other portions of the support surface. Thus, any dirt orother contaminants lying on those portions of the ferrule that are notcontacted by the rib of the support element will not adversely affectthe precision with which the front surface of the ferrule is polished.

[0041] The support element 30 can include different numbers of ribs 32and ribs of various shapes, as shown in FIGS. 3 and 4 in which theferrule 10 is depicted independent of the connector housing for purposesof clarity. For example, the support element can include a pair ofparallel ribs as depicted in FIG. 3. Alternatively, the support elementcan include a T-shaped rib as shown in FIG. 4. Regardless of the numberof ribs or the configuration of the ribs, the support element ispreferably designed such that the ribs can contact the ferrule after-theferrule is assembled into a connector. For example, the support elementis designed such that the contact element, such as the ribs, can beinserted through the rib slots or other openings defined by theconnector housing and into contact with the ferrule. In embodiments inwhich lengthwise extending grooves 16 are defined in both opposed majorsurfaces of the ferrule, the ribs are preferably sized and positioned soas not to fall into the grooves. With respect to the embodiment of FIG.4, for example, the crossbar portion of the T-shaped rib is preferablybroader than the groove defined by the ferrule such that the T-shapedrib does not fall within the groove defined by the ferrule. As such, therib of this embodiment need not necessarily include the stem portion.

[0042] While the support element 30 is depicted to include all of theribs 32, the ferrule 10 could include one or more ribs. In contrast tothe support surface that is illustrated and described above, the supportsurface of this embodiment of the support element could be planar sincethe only contact between the support element and the ferrule would bealong the ribs defined by the ferrule.

[0043] In operation, a ferrule 10 according to the present invention ispreassembled into a connector, and the connector is then inserted intothe polishing jig 20. As shown in FIGS. 2A-2C and described above, thejig of one advantageous embodiment includes a jig body 24 and thepivotable support element 30. At least one of the jig body and thesupport element can be moved, such as by mechanical means such as acam-type actuator, in a direction alternately toward and away from theother. In the embodiment illustrated in FIGS. 2A-2C, for example, thesupport element is adapted to be alternately moved toward and away fromthe jig body. However, the polishing jig can be designed such that thejig body is movable relative to the support element, if so desired.

[0044] With reference to the illustrated embodiment in which the supportelement 30 is movable relative to the jig body 24, the polishing jig 20is initially opened by rotating the hub 26 to bring the protrudingmedial portion 26 b into contact with the proximal end of the arm 28,thereby causing the arm to move radially outward which spaces thesupport element from the jig body. The connector can then be insertedinto the polishing jig so as to rest on the pivotable support element.In this regard, the ferrule 10 is preferably positioned upon the supportsurface of the support element such that the ribs 32 protrude throughthe rib slots or holes/apertures of the connector housing and contactthe ferrule. Once the connector has been properly positioned between thejig body and the support element, the hub is again rotated such that arecessed lateral portion 26 c is moved into contact with the proximalend of the arm such that the bias member draws the arm radially inwardand the support element is moved into engagement with the ferrule. Inthis regard, the jig body is moved into position such that the outwardlyprotruding alignment member 22 of the jig body extends through the ribslot of the connector housing and engages the lengthwise extendinggroove 12 defined by the ferrule. As such, the ferrule will be securelyheld in an aligned position between the jig body and the support elementsuch that the front surface 12 of the ferrule can then be polished. Oncepolishing operations are completed, the support member is again movedout of contact with the ferrule by further rotating the hub and thepolished connector can then be removed from the polishing jig. Byinserting and removing the connector while the polishing jig is open,the sliding contact between the ferrule and the jig body and the supportelement is significantly reduced, thereby correspondingly reducing thewear and increasing the lifetime of the jig body and the supportelement.

[0045] The polishing jig 20 of the present invention can be formed in avariety of different manners without departing from the spirit and scopeof the present invention. For example, the polishing jig of anotherembodiment is depicted in FIGS. 5A and 5B. As shown in FIG. 5A, thepolishing jig of this embodiment includes a support element 30 that ismounted upon and fixed to the platform 23. While a support elementhaving a T-shaped rib is depicted, the support element can have avariety of other configurations as described-above in conjunction withthe embodiment of FIGS. 2A-2C. In addition, the polishing jig includesajig body 24 pivotably mounted to an arm 28 of the polishing jig. Asdescribed above in conjunction with other embodiments, the jig bodyincludes a contact element, such as an alignment feature and, moreparticularly, such as an alignment rib 22 for engaging a complimentaryalignment feature, such as an alignment groove 16, defined by theferrule 10. Although not shown, the arm can also be mounted so as topivot or otherwise rotate relative to the platform as described above inconjunction with the embodiment of FIGS. 2A-2C. In this regard, thepolishing jig can include a cam or other mechanical means for adjustingthe separation between the jig body and the support element as the armis rotated relative to the platform.

[0046] In order to more fully illustrate the manner in which thepolishing jig 20 of the present invention is capable of securelyengaging in holding a ferrule 10 during polishing operations followingpreassembly of the connector 44 including assembly of the ferrule intothe connecting housing 40, reference is now made to FIG. 5B. As shown,the preassembled connector is inserted through a window 28 a defined bythe arm 28 such that the forward end of the connector is disposedbetween the jig body 24 and the support element 30. The arm is thenrotated such that the jig body is moved toward the support element. Assuch, the contact element of the jig body, such as the alignment rib 22,is inserted through an opening 42 defined by the connector housing andengages the corresponding alignment feature, such as the alignmentgroove 16, defined by the ferrule. Concurrently, the contact element ofthe support element is inserted through another opening defined by theconnector housing so as to engage another side of the ferrule, typicallyopposite the side engaged by the jig body. In the embodiment depicted inFIGS. 5A and 5B, for example, the stem portion of the T-shaped rib isinserted through the opening defined by the connector housing to engagethe ferrule, while the crossbar portion of the T-shaped rib also engagesthe ferrule, albeit a forward portion of the ferrule that protrudesbeyond the connecting housing. As such, the polishing jig and theferrule of the present invention permit the ferrules of preassembledconnectors to be readily polished.

[0047] According to the present invention, the ferrule 10 and thepolishing jig 20 each include complimentary alignment features thatcooperate to permit a ferrule, including a multifiber ferrule, to bepreassembled into a fiber optic connector prior to being polished. As aresult of the engagement of the ferrule's alignment feature, such as alengthwise extending groove 16, by the polishing jig's alignmentfeature, such as an outwardly protruding alignment member 22 carried bya jig body 24, the ferrule is held in a precisely aligned positionduring the polishing operations without requiring the entire exteriorsurface of the ferrule to be defined to within very tight tolerances. Assuch, the ferrule and the polishing jig of the present invention providean economical and efficient technique for precisely polishing the frontsurface 12 of the ferrule following the assembly of the ferrule into afiber optic connector.

[0048] Many modifications and other embodiments of the invention willcome to mind to one skilled in the art to which this invention pertainshaving the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

That which is claimed:
 1. A ferrule comprising: a ferrule body extendinglongitudinally between opposed front and rear surfaces, said ferrulebody having first and second major sides and first and second minorsides, said first and second major sides being larger than said firstand second minor sides, wherein said ferrule body defines alongitudinally extending groove in at least one of said first and secondmajor surfaces.
 2. The ferrule according to claim 1 wherein the groovehas a V-shape in lateral cross-section.
 3. The ferrule according toclaim 2 wherein the V-shaped groove is truncated such that the groove isdefined by a pair of sloping sidewalls and a bottom surface extendingbetween the pair of sloping sidewalls.
 4. The ferrule according to claim1 wherein the groove is defined to extend longitudinally through amedial portion of the respective major surface.
 5. The ferrule accordingto claim 4 wherein said ferrule body defines a plurality of opticalfiber bores and a pair of guide pin openings on opposite sides of theoptical fiber bores, and wherein the groove is also disposed between thepair of guide pin openings.
 6. The ferrule according to claim 1 whereinsaid ferrule body defines a pair of longitudinally extending grooveswith one groove defined in each of said first and second major surfacessuch that said ferrule body has a bowtie shape in lateral cross-section.7. A ferrule comprising: a ferrule body extending longitudinally betweenopposed front and rear surfaces and having a plurality of sides, saidrear surface defining a substantially rectangular shape in lateralcross-section, wherein said ferrule body defines a longitudinallyextending groove in at least one side thereof.
 8. The ferrule accordingto claim 7 wherein the groove has a V-shape in lateral cross-section. 9.The ferrule according to claim 8 wherein the V-shaped groove istruncated such that the groove is defined by a pair of sloping sidewallsand a bottom surface extending between the pair of sloping sidewalls.10. The ferrule according to claim 7 wherein the groove is defined toextend longitudinally through a medial portion of the respective majorsurface.
 11. The ferrule according to claim 10 wherein said ferrule bodydefines a plurality of optical fiber bores and a pair of guide pinopenings on opposite sides of the optical fiber bores, and wherein thegroove is also disposed between the pair of guide pin openings.
 12. Theferrule according to claim 7 wherein said ferrule body defines at leastone longitudinally extending groove in each of a pair of opposed sidesof said ferrule body such that said ferrule body has a bowtie shape inlateral cross-section.
 13. A jig for holding a ferrule during polishingoperations, the jig comprising: a jig body comprising an alignmentfeature for cooperating with a complimentary alignment feature of theferrule, wherein said alignment feature of said polishing jig isselected from the group consisting of an alignment groove and anoutwardly protruding alignment member, and wherein said alignmentfeature of said polishing jig is selected from the group such that saidpolishing jig includes one type of alignment feature and the ferruleincludes the other type of alignment feature; and a support elementhaving a support surface capable of engaging another portion of theferrule opposite the portion of the ferrule engaged by said jig body tothereby hold the ferrule in an aligned position during polishingoperations, wherein at least one of said jig body and said supportelement is capable of pivoting.
 14. The jig according to claim 13wherein said alignment feature of said polishing jig is selected fromthe group consisting of a V-shaped alignment groove and an outwardlyprotruding alignment member having a semicircular shape incross-section.
 15. The jig according to claim 13 wherein said alignmentmember of said jig body comprises a lengthwise extending alignment rib.16. The jig according to claim 15 wherein said support element pivotsabout an axis perpendicular to said lengthwise extending alignment rib.17. The jig according to claim 13 wherein said support surface of saidsupport element comprises at least one rib protruding outwardly relativeto other portions of said support surface.
 18. The jig according toclaim 17 wherein said at least one rib comprises a pair of parallelribs.
 19. The jig according to claim 17 wherein said at least one ribcomprises a T-shaped rib.
 20. A jig for polishing a preassembledconnector having a connector housing and a ferrule mounted at leastpartially therein, the jig comprising: a jig body having a contactelement for engaging one side of the ferrule; and a support elementhaving a support surface with at least one contact element for engaginganother side of the ferrule, wherein the contact elements of both saidjig body and said support element are sized to be smaller than openingsdefined by the connector housing such that the contact elements of saidjig body and said support element are capable of being inserted throughthe openings defined by the connector housing and into contact with theferrule in order to hold the ferrule of the preassembled connector in analigned position between said jig body and said support element duringpolishing operations.
 21. The jig according to claim 20 wherein thecontact element of said jig body comprises an alignment feature forengaging a complimentary alignment feature of the ferrule.
 22. The jigaccording to claim 21 wherein the alignment feature of said jig body isselected from the group consisting of an alignment groove and anoutwardly protruding alignment member, and wherein the alignment featureof said jig body is selected from the group such that said jig bodyincludes one type of alignment feature and the ferrule includes theother type of alignment feature.
 23. The jig according to claim 22wherein the alignment member of said jig body comprises a lengthwiseextending alignment rib.
 24. The jig according to claim 20 wherein thecontact element of said support element comprises at least one ribprotruding outwardly relative to other portions of the support surface.25. The jig according to claim 24 wherein said at least one ribcomprises a pair of parallel ribs.
 26. The jig according to claim 24wherein said at least one rib comprises a T-shaped rib.
 27. A method forpolishing a preassembled connector having a connector housing and aferrule mounted at least partially therein, the method comprising:mounting the preassembled connector within a polishing jig having a jigbody and a support element; inserting a contact element of the jig bodythrough an opening defined by the connector housing and into engagementwith one portion of the ferrule; inserting a contact element of thesupport element through an opening defined by the connector housing andinto engagement with another portion of the ferrule; and polishing afront face of the ferrule while the ferrule of the preassembledconnector is held in an aligned position between the jig body and thesupport element.
 28. The method according to claim 27 wherein thecontact element of the jig body comprises an alignment rib, and whereinsaid step of inserting the contact element of the jig body through theopening defined by the housing comprises inserting the alignment ribinto a groove defined by the ferrule for engagement therewith.
 29. Themethod according to claim 28 wherein said step of inserting thealignment rib into a groove defined by the ferrule comprisesestablishing contact with the ferrule along at least two lines.
 30. Themethod according to claim 27 wherein the support element is capable ofpivoting, and wherein said step of inserting the contact element of thejig body through the opening defined by the connector comprisespivotably supporting the ferrule with the support element.